Various proposals have been made in the past for electric-powered vehicles. To date, for a number of reasons, electric vehicle systems have yet to become generally commercially viable for urban and highway applications. There have been proposals to employ zinc-air batteries for urban vehicle propulsion. An example is the publication "Improved Slurry Zinc-Air Systems as Batteries for Urban Vehicle Propulsion", by P. C. Foller, Journal of Applied Electrochemistry, Vol. 16, pp. 527-543 (1986).
Metal-air battery structures are described in the following publications: U.S. Pat. No. 4,842,963, entitled "Zinc Electrode and Rechargeable Zinc-Air Battery"; U.S. Pat. No. 4,147,839, entitled "Electrochemical Cell with Stirred Slurry"; U.S. Pat. No. 4,908,281, entitled "Metal-Air Battery with Recirculating Electrolyte"; U.S. Pat. No. 3,847,671, entitled "Hydraulically-Refuelable Metal-Gas Depolarized Battery System"; U.S. Pat. No. 4,925,744, entitled "Primary Aluminum-Air Battery"; U.S. Pat. No. 3,716,413, entitled "Rechargeable Electrochemical Power Supply"; U.S. Pat. No. 4,925,744, entitled "Primary Aluminum-Air Battery".
In U.S. Pat. No. 3,592,698, entitled "Metal Fuel Battery with Fuel Suspended in Electrolyte", there is described inter alia a method for circulating an electrolyte/metal fuel powder mixture through the batteries; U.S. Pat. No. 4,126,733, entitled "Electrochemical Generator Comprising an Electrode in the Form of a Suspension" relates to a similar subject, using a circulated suspension of inert cores coated with an electrochemically active material. In U.S. Pat. No. 4,341,847, entitled "Electrochemical Zinc-Oxygen Cell", there is described a method in which an electrolyte is circulated in the annular space between concentric electrodes.
Electrical energy storage systems are described in the following publications: U.S. Pat. No. 4,843,251, entitled "Energy Storage and Supply Battery with Recirculating Electrolyte"; "Energy on Call" by John A. Casazza, et al., IEEE Spectrum, June 1976, pp. 44-47; U.S. Pat. No. 4,275,310, entitled "Peak Power Generation"; U.S. Pat. No. 4,124,805, entitled "Pollution-Free Power Generating and Peak Power Load Shaving System"; U.S. Pat. No. 4,797,566, entitled "Energy Storing Apparatus".
Regeneration of spent zinc-containing alkaline electrolyte is described in a number of prior patents. For example, in U.S. Pat. No. 3,847,671 (mentioned above), whole spent electrolyte is subjected to electrolysis, when zinc deposited at the cathode is removed with a wiper blade. The thus-removed zinc is said to be substantially heavier than the electrolyte (35-40% KOH) and hence falls to the bottom of each cell. In a particular embodiment, the cathode and anode are specified as being made from copper (or silver-plated copper) and carbon, respectively. In U.S. Pat. No. 3,981,747, it is proposed to regenerate the spent zinc in an alkaline electrolyte by reaction with a strongly electropositive metal, such as magnesium or aluminum, which displaces the zinc. In U.S. Pat. No. 4,341,847 (also mentioned above), spent zinc in the alkaline electrolyte is regenerated either by reversing the current and plating zinc on the anode, or by mechanically replacing zinc oxide particles by active zinc particles.
Moreover, it is of importance in batteries containing zinc electrodes that the zinc should not be consumed by a reaction with aqueous electrolyte, especially alkaline electrolyte which generates hydrogen gas, which reaction merely corrodes the zinc and prevents its availability for producing electric current. A number of prior patents relate to this problem.
Thus, e.g., in U.S. Pat. No. 4,112,205, double salts containing both mercuric and quaternary ammonium ions are used as inhibitors in galvanic cells comprising zinc anodes, notably in Leclanche-type batteries containing ammonium chloride/zinc chloride electrolyte; U.S. Pat. No. 3,945,849 employs quaternary ammonium halides as inhibitor for zinc anodes in similar primary cells. U.S. Pat. No. 4,195,120 teaches alkaline cells containing a predominantly zinc anode and, as a hydrogen evolution inhibitor, a surfactant which is an organic phosphate ester of the ethylene oxide adduct type. Metal oxide inhibitors for zinc (in practice ZnO) electrodes are described in U.S. Pat. No. 4,084,047, in which the inhibitors are mixed thoroughly into the ZnO; the inhibitors taught in this patent are binary combinations of oxides which exclude mercuric oxide, the latter being regarded as an ecologically unsatisfactory additive for the ZnO electrode. According to U.S. Pat. No. 4,084,047, it was known to mix or alloy the active zinc in zinc-zinc oxide anodes and their supporting grid (e.g., copper or silver structures) with 0.5-5.0 wt. % mercury or mercuric oxide.
It will also be appreciated by persons skilled in the art that amalgamation of zinc with mercury has been known for a very long time, and that it is carried out in neutral, or more usually, in acid, solution, e.g., by reacting zinc with mercury chloride in dilute hydrochloric acid.
In U.S. patent application Ser. No. 636,411, there is described and claimed a process for the regeneration of an at least partially-spent slurry having a dissolved phase and an undissolved phase for use in metal-air batteries.
In U.S. patent application Ser. No. 636,426, there is described and claimed a method for the inhibition of corrosion in particulate zinc.
The disclosures; of all of the foregoing publications (including patents), including also the prior art described therein, are explicitly incorporated herein by reference.